A 16 bit SMS message that contains an odd message length value will
cause the message decoding loop to run forever. The message buffer is
not on the stack but will be overflowed resulting in corrupted memory
and an immediate crash.

External control protocols, such as the Asterisk Manager Interface,
often have the ability to get and set channel variables; this allows
the execution of dialplan functions. Dialplan functions within
Asterisk are incredibly powerful, which is wonderful for building
applications using Asterisk. But during the read or write execution,
certain diaplan functions do much more. For example, reading the SHELL()
function can execute arbitrary commands on the system Asterisk is
running on. Writing to the FILE() function can change any file that
Asterisk has write access to. When these functions are executed from an
external protocol, that execution could result in a privilege escalation.

Stack Overflow in HTTP Processing of Cookie Headers. Sending a HTTP
request that is handled by Asterisk with a large number of Cookie
headers could overflow the stack. You could even exhaust memory if you
sent an unlimited number of headers in the request.

Denial of Service Through File Descriptor Exhaustion with chan_sip
Session-Timers. An attacker can use all available file descriptors
using SIP INVITE requests. Asterisk will respond with code 400, 420,
or 422 for INVITEs meeting this criteria.
Each INVITE meeting these conditions will leak a channel and several
file descriptors. The file descriptors cannot be released without
restarting Asterisk which may allow intrusion detection systems to be
bypassed by sending the requests slowly.

Remote Crash Vulnerability in PJSIP channel driver. A remotely
exploitable crash vulnerability exists in the PJSIP channel driver if
the "qualify_frequency" configuration option is enabled on an AOR and
the remote SIP server challenges for authentication of the resulting
OPTIONS request. The response handling code wrongly assumes that a
PJSIP endpoint will always be associated with an outgoing request which
is incorrect.